Foundation structure

ABSTRACT

This invention provides a foundation structure ( 10 ) cast from a settable material such as concrete and comprises a slab ( 12 ) having a particular generally annular non-rectangular circumferential outer profile. The foundation structure ( 10 ) is further provided with a plurality of intsecting primary beams ( 14 ) extending through a common central region of the slab ( 12 ); and a secondary annular circumferentially extending beam ( 16 ). The structure ( 10 ) is constructed by a method including the steps of forming a plurality of radially extending primary channels extending through a central foundation region of the building; forming a secondary annular circumferentially extending channel; providing a void former for defining a common central region of intersecting channels, through which the primary beams ( 14 ) extend after being cast; casting a settable material into the channels; and casting a slab of settable material integrally with the primary and secondary beams ( 14, 16 ).

INTRODUCTION AND BACKGROUND TO THE INVENTION

[0001] This invention relates to a foundation structure for a building, a building provided with such a foundation structure and a method of constructing a foundation structure.

[0002] A known foundation structure comprises a plurality of intersecting elongate beams arranged in a grid. The known structure is particularly suitable for erecting buildings on top of problem soil such as clay. Such foundation is, however, more suitable for erecting building structures which are rectangular in plan view.

OBJECT OF THE INVENTION

[0003] It is accordingly an object of the present invention to provide a foundation structure for a building, a building provided with such a foundation structure and a method of constructing a foundation structure, which are cost-effective useful alternatives to the known foundation structures, and methods.

SUMMARY OF THE INVENTION

[0004] According to a first aspect of the invention there is provided a foundation structure for a building of the type having a non-rectangular annular circumferential profile, the foundation structure comprising a plurality of radially extending primary beams of a settable material extending through a central foundation region of the building.

[0005] Preferably the building has a circular circumferential outer profile.

[0006] Alternatively, the foundation structure may have an elliptic circumferential outer profile.

[0007] Further alternatively the foundation structure may have a hexagonal circumferential outer profile.

[0008] Even further alternatively the foundation structure may have an octagonal circumferential outer profile.

[0009] A secondary annular beam may be provided along the circumference of the foundation structure.

[0010] An intermediate annular beam disposed concentrically with the secondary annular beam may be provided between the secondary beam and said central region.

[0011] A slab of settable material may be cast integrally with the beams.

[0012] The beams may extend through a common central point.

[0013] Further according to the invention the common central point is formed by a void former encasing a central region of the beams.

[0014] According to a second aspect of the invention there is provided a building having the above foundation structure.

[0015] According to a third aspect of the invention there is provided a method of constructing a foundation structure for a building of the type having a non-rectangular annular circumferential profile, the method including the steps of forming a plurality of radially extending primary channels extending through a central foundation region of the building; and casting a settable material into the channels to form a plurality of radially extending beams.

[0016] The method may include the further step of, prior to casting the beams, providing a void former for defining a common central region of intersecting channels, through which the beams extend after being cast.

[0017] According to a fourth aspect of the invention there is provided a void former comprising a base and a plurality of walls extending from the base, the walls being arranged such that a plurality of channels intersecting in a -common region are defined by the walls.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention will now be described further by way of non-limiting examples with reference to the accompanying drawings wherein

[0019] FIGS. 1 to 4 are views from below of foundation structures according to first to fourth embodiments of the invention;

[0020]FIG. 5 is a plan view of a void former for defining a common central region of intersecting channels for the foundation structures of FIGS. 1 to 4; and

[0021]FIG. 6 is a cross-sectional side view along line a-a in FIG. 5, in use, prior to settable material being cast into the channels.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0022] Referring to FIGS. 1 to 4, foundation structures according to four embodiments of the invention, are generally designated by reference numerals 10 a to 10 d.

[0023] The foundation structures 10 a to 10 d are generally similar in that each foundation structure 10 is cast from a settable material such as concrete and comprises a slab 12 having a particular generally annular non-rectangular circumferential outer profile, which is described in more detail below.

[0024] Each foundation structure 10 is further provided with a plurality of intersecting primary beams 14 extending through a common central region of the slab 12; and a secondary annular circumferentially extending beam 16. Depending on particular dimensions that are selected, the foundation structures 10 are optionally provided with a tertiary annular beam 18 (FIG. 1) arranged concentrically with the secondary beam 16, intermediate the secondary beam 16 and the central region.

[0025] Referring to FIGS. 5 and 6, a void former 20 is provided for defining a common central region of intersecting channels, through which the beams extend after being cast. The void former 20 is made of any suitable material such as cardboard, wood, fibreboard, and/or a plastics material. The void former 20 comprises a base 20.1 and a plurality of upstanding walls 20.2, arranged in pairs. The walls 20.2 in a pair meet in a pointed end and the walls are arranged such that a plurality of triangular spaces 20.3 are defined for receiving soil backfill. The channels 20.4 are defined by the walls 20.2 between the triangular spaces, for receiving the settable material, as described in more detail below.

[0026] The foundation structures 10 are constructed by a general method including the steps of:

[0027] forming a plurality of radially extending primary channels extending through a central foundation region of a building to be constructed;

[0028] forming a secondary annular circumferentially extending channel;

[0029] optionally forming a tertiary annular channel extending concentric with the secondary channel intermediate the secondary channel and the central region;

[0030] positioning the void former 20 to define a common central region of intersecting channels, through which the primary beams 14 extend after being cast;

[0031] casting a settable material into the channels to form the primary, secondary and optionally the tertiary beams 14, 16 and 18; and

[0032] casting a slab of settable material integrally with the primary, secondary and optionally the tertiary beams 14, 16 and 18.

[0033] Referring to FIG. 1, the foundation structure 10 a has a circular circumferential outer profile and is provided with an intermediate annular beam 18 disposed concentrically with the secondary beam 16, between the secondary beam 16 and the central region.

[0034] Referring to FIG. 2, the foundation structure 10 b has a generally octagonal circumferential outer profile.

[0035] Referring to FIG. 3, the foundation structure 10 c has a generally hexagonal circumferential outer profile.

[0036] Referring to FIG. 4, the foundation structure 10 d has a generally elliptic circumferential outer profile.

[0037] The applicant has found that with a foundation structure 10 according to the various embodiments of the invention, substantially less concrete is required in the construction of the foundation structure in problem soil conditions, than with conventional foundation structures.

[0038] It will be appreciated that variations in detail are possible with a foundation structure for a building, a building provided with such a foundation structure and a method of constructing a foundation structure according to the present invention without departing from the scope of the appended claims. 

1. A foundation structure for a building of the type having a non-rectangular annular circumferential profile, the foundation structure comprising a plurality of radially extending primary beams of a settable material extending through a central foundation region of the building; and a slab of settable material cast integrally with the beams.
 2. A foundation structure according to claim 1 wherein the building has a circular circumferential outer profile.
 3. A foundation structure according to claim 1 wherein the foundation structure has an elliptic circumferential outer profile.
 4. A foundation structure according to claim 1 wherein the foundation structure has a hexagonal circumferential outer profile.
 5. A foundation structure according to claim 1 wherein the foundation structure has an octagonal circumferential outer profile.
 6. A foundation structure according to any one of the preceding claims wherein a secondary annular beam is provided along the circumference of the foundation structure.
 7. A foundation structure according to claim 6 wherein an intermediate annular beam disposed concentrically with the secondary annular beam is provided between the secondary beam and said central region.
 8. A foundation structure according to claim 1 wherein the beams extend through a common central point.
 9. A foundation structure according to claim 8 wherein the common central point is formed by a void former encasing a central region of the beams.
 10. (Cancelled)
 11. A building having a foundation structure according to claim
 1. 12. A method of constructing a foundation structure for a building of the type having a non-rectangular annular circumferential profile, the method including the steps of forming a plurality of radially extending primary channels extending through a central foundation region of the building; casting a settable material into the channels to form a plurality of radially extending beams; and casting a slab of settable material integrally with the beams.
 13. A method of constructing a building according to claim 12 which includes the further step of, prior to casting the beams, providing a void former for defining a common central region of intersecting channels, through which the beams extend after being cast.
 14. (Cancelled)
 15. A void former comprising a base and a plurality of walls extending from the base, the walls being arranged such that a plurality of radially extending channels intersecting in a common region are defined by the walls.
 16. (Cancelled). 